DE 43 30 170 C2 disclosed a six-gear dual clutch transmission designed on the input side with a so-called dual clutch formed by two frictionally coupled shifting elements. In this dual clutch transmission, input torque of a prime mover applied via a motor output shaft, depending on a transmitting capacity adjusted at the time in the shifting elements, is passed to a first central input shaft or to a second input shaft supported on the central input shaft and designed as a hollow shaft. The input central shaft and the input hollow shaft are each non-rotatably connected with one gear wheel which, in turn, meshes with respective gear wheels, each non-rotatably connected with one countershaft. Both countershafts are disposed concentrically to each other, one countershaft designed as a hollow shaft being supported on one other central countershaft.
To produce different gear steps, the six-gear dual clutch transmission is designed with added gear wheel pairs connectable via synchronizer units, the input torque of the prime mover changed according to the total ratio of the transmission adjusted at the moment being relayed via a transmission output shaft disposed coaxially to the transmission input.
The strong toothing forces acting in the area of the gear wheel pairs connected with the input shaft designed as a hollow shaft, hereinafter designated as a transmission input hollow shaft, are introduced in the transmission housing via supports on the housing side. The forces engaging on the input central shaft are introduced in the housing via bearing devices on the housing side of the input central shaft.
This arrangement, however, is disadvantageously distinguished by unfavorable load characteristic values which result in a short service life of the transmission and undesirable with regard to the operation costs of a motor vehicle throughout the service life thereof. Furthermore, supports of wheel sets on the housing side, in general, increase the production costs and the required installation space of a transmission, in addition, making and assembly difficult.
Accordingly, the problem on which this invention is based is to make a transmission device of countershaft type available which, in the area of the bearings of the input shafts, stands out by low load characteristic values, long service life and easy assemblage.